The applicants proposed to develop an x-ray beam equalization technique for digital fluoroscopic applications that will produce an equalized radiograph with minimal image artifacts and tube loading. More specifically the aim are: (1) Investigation of the effect of piston size and the extent of focal spot blurring on image equalization using physical phantoms. (2) design and construction of the necessary hardware and software for an automated image equalization system. (3) Investigation of the hypothesis that x-ray beam equalization produces an image with significantly improved signal-to-noise ratio (S/N) and minimal image artifacts using physical phantoms. (4) Investigation of the hypothesis that x-ray beam equalization produces significantly improved iodine quantification using physical phantoms. (5) Investigation of the hypothesis that the x-ray beam equalization technique can be reliably utilized during coronary angiography using a swine animal model. The results of this research will provide fundamentally improved images for both low and high frame rate applications. This technique has several potential applications. One of the applications is the elimination of bright spots and improvement of image S/N in digital angiographic images. This is particularly true for cardiac imaging where the heart is very dense near a very transmissive lung field which causes a significant S/N degradation over the heart region. The elimination of bright spots by x-ray beam equalization allows the entire image to be acquired with optimal S/N. Furthermore, this technique provides significantly improved iodine quantification in the under penetrated regions of the image.